Astilbe plant named ‘White Sensation’

ABSTRACT

A new cultivar of  Astilbe simplicifolia  hybrid named ‘White Sensation’ that is characterized by its pure white flowers borne on upright to cascading panicles over very dark green foliage and combined with a compact plant habit.

Botanical classification: Astilbe simplicifolia hybrid.

Varietal denomination: ‘White Sensation’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Astilbesimplicifolia and will be referred to hereafter by its cultivar name,‘White Sensation’. ‘White Sensation’ represents a new Astilbe, anherbaceous perennial grown for landscape use.

The inventor discovered the new cultivar, ‘White Sensation’, as a chanceseedling that arose in a cultivated area in Noorden, The Netherlands inthe summer of 1993. Although the parentage is unknown, thecharacteristics of the new cultivar and the presence of the cultivarsAstilbe simplicifolia hybrid ‘Sprite’ (not patented) and Astilbejaponica hybrid ‘Ellie’ (not patented) in the area suggest that they arelikely parents.

The new cultivar ‘White Sensation’ was selected as unique for having theplant habit of ‘Sprite’ combined with dark colored foliage and whiteflowers.

Asexual reproduction of the new cultivar was first accomplished bytaking divisions in De Hoef, The Netherlands in 1995. It has beendetermined that the characteristics of the new cultivar are stable andare reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and represent thecharacteristics of the new cultivar after observing plants grownoutdoors in a field and in containers for two years in De Hoef, TheNetherlands. These attributes in combination distinguish ‘WhiteSensation’ from all other varieties of Astilbe known to the inventor.

-   -   1. ‘White Sensation’ exhibits dark green foliage    -   2. ‘White Sensation’ exhibits white flowers presented on upright        to arched panicles.    -   3. The plant habit of ‘White Sensation’ is clump-forming,        broadly upright, and compact.    -   4. ‘White Sensation’ is cold hardy at least to U.S.D.A. Zones 5.

‘White Sensation’ is most closely related to the likely parents, Astilbesimplicifolia hybrid ‘Sprite’ and Astilbe japonica hybrid ‘Ellie’. Whitesensation is similar to ‘Sprite’ in plant habit, but differs in havingwhite flowers rather than light pink flowers and in having darker greenfoliage. ‘White Sensation’ is similar to ‘Ellie’ in having pure whiteflowers, however ‘White Sensation’ differs in having a more compactplant habit and darker colored foliage. ‘White Sensation’ can also becompared to the white flowered Astilbe ‘Snowdrift’ (not patented),however it is an Astilbe×arendsii hybrid and has lighter, medium greencolored foliage.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The plants and plant parts in the photographs depict a two-year oldplant of ‘White Sensation’ as grown outdoors in a 20 cm container in DeHoef, The Netherlands.

The photograph on the first sheet provides an overall view of the newAstilbe in bloom.

The photograph on the top of the second sheet is a close-up view of theflowers of ‘White Sensation’ and the photograph on the bottom of thesecond sheet is a close-up view of a leaf of ‘White Sensation’.

The colors in the photographs are as close as possible with thephotographic and printing technology utilized. The color values cited inthe detailed botanical description accurately describe the colors of thenew Astilbe.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of two year-old plants of thenew cultivar as grown outdoors in 20 cm containers in De Hoef, TheNetherlands for 2 years with average day temperatures ranging from 14°C. to 35° C. and average night temperatures ranging from 10° C. to 18°C. The phenotype of the new cultivar may vary with variations inenvironmental, climatic, and cultural conditions, as it has not beentested under all possible environmental conditions. The colordetermination is in accordance with the 2001 R.H.S. Colour Chart of TheRoyal Horticultural Society, London, England, except where general colorterms of ordinary dictionary significance are used.

-   Botanical classification: ‘White Sensation’ is an Astilbe    simplicifolia hybrid.-   Parentage: Naturally occurring chance seedling of Astilbe    simplicifolia hybrid, parentage is unknown with Astilbe    simplicifolia hybrids ‘Sprite’ and ‘Ellie’ as likely parents.-   General description:    -   -   Blooming period.—Begins in mid July and continues for about            6 weeks.        -   Plant type.—Herbaceous perennial.        -   Plant habit.—Clump-forming, dwarf, compact, and broadly            upright.        -   Height and spread.—Average of 46 cm in height, 50 cm in            spread.        -   Hardiness.—Known to be hardy at least to U.S.D.A. Zone 5,            colder zones have not been tested.        -   Culture.—Prefers humus-rich, moist but well-drained soils in            partial shade or full sun in areas where summers are cool            with sufficient moisture.        -   Diseases and pests.—No unique susceptibility or resistance            to diseases or pests has been observed.        -   Root description.—Fine, wiry, dark colored and freely            branched.-   Growth and propagation:    -   -   Propagation.—Stem division.        -   Cropping time.—Roots fully develop in 22 cm pot in about 20            weeks from a one eye stem division.        -   Growth rate.—Moderate growth rate.-   Stem description (flowering stems):    -   -   Stem color.—Young and mature stems; 144A with 187A to 187B            near base.        -   Stem size.—Average of 28.6 cm in length and 2 mm in            diameter.        -   Stem quantity.—Average of 10 per 22 cm container.        -   Stem surface.—Slightly glossy and pubescent with a sparse            covering of soft hairs about 2 mm in length and N167B in            color.        -   Stem aspect.—Strong, mostly held upright.        -   Branching habit.—No lateral branches, flowering stems emerge            from a basal rosette of foliage.-   Foliage description:    -   -   Leaf division.—Bi-ternate.        -   Leaf attachment.—Petiolate.        -   Leaf arrangement.—Alternate.        -   Leaf number.—Average of 3 per flowering stem and an average            of 3 basal leaves per stem.        -   Internode length.—Average of 7.6 cm.        -   Leaf size.—Average of 14.6 cm in length and 17.3 cm in            width.        -   Leaflet quantity.—Average of 21 per leaf.        -   Leaflet shape.—Terminals; narrow ovate to narrow elliptic,            laterals; narrow ovate.        -   Leaflet base.—Attenuate.        -   Leaflet apex.—Acute.        -   Leaflet venation.—Pinnate, not conspicuous, color on upper            lower surface 148B, color on lower surface 148A.        -   Leaflet margins.—Biserrate.        -   Leaflet size.—Lateral leaflets; average of 2.4 cm in length            and 1.1 cm in width, terminal leaflets; average of 3.2 cm in            length and 2.2 cm in width.        -   Leaflet surface.—Upper surface; slightly rugose, lower            surface; sparsely pubescent with short strigose hairs an            average of 1 mm in length and 157A to 157D in color            (especially prevelant on main viens), glossy, rough to            touch.        -   Leaflet color.—Young foliage upper surface; 143A, young            foliage lower surface; 143C to 144A, mature foliage upper            surface; darker than 137A, mature foliage lower surface;            137B to 137C.        -   Petioles.—144A in color with base of 187B, average of 1 mm            in diameter and 8.3 cm in length, surface is glabrous.        -   Petiolules.—144A in color with base of 187B, average of 1 mm            in diameter and 2.3 cm in length, surface is glabrous.-   Flower description:    -   -   Inflorescence type.—Numerous single rotate shaped flowers            arranged on pyramidal panicles.        -   Inflorescence aspect.—Upright and cascading.        -   Inflorescence size.—Average of 17.4 cm in height and 15.5 cm            in width.        -   Flower fragrance.—Faint, sweet.        -   Flower quantity.—Average of 750 per inflorescence,            approximately 7,500 flowers per plant.        -   Flower lastingness.—Average of 10 days per flower, panicles            blooms for about 6 weeks, flowers persistent.        -   Flower buds.—Ovate in shape, average of 1.5 mm in diameter            and 2 mm in length, 157D in color and 145A near base.        -   Flower aspect.—Upright, outward, and drooping.        -   Flower shape.—Rotate.        -   Flower size.—About 4 mm in depth and 8 mm in diameter.        -   Petals.—Average of 5, separate, narrow obovate in shape,            margin is entire, apex is obtuse, upper and lower surface is            glabrous and dull, color of upper and lower surface (opening            and mature) is pure white and whiter than any R.H.S. colour            chart, color fades to 175A, average of 5 mm in length and 1            mm in width.        -   Calyx.—Campanulate, sepals fused at base, average of 3 mm in            length and 4 mm in diameter.        -   Sepals.—5, ovate in shape, margin is entire, apex is obtuse,            base is cuneate and fused, surface is smooth and dull, color            of upper and lower surface when immature; 145C, color of            upper and lower surface when mature; pure white (whiter than            R.H.S. colour chart) with a base of 155D, about 1 mm in            width and 1.5 mm in length.        -   Bracts.—2, lanceolate in shape, 144B in color, unequal with            one about 1 mm in width and 3 mm in length and the other            about 0.75 mm in width and 1.5 mm in length, attenuate apex,            base fused to rachis, color between 155B and 145D with upper            portion 71A.        -   Peduncles.—Average of 17.1 cm in length and 1.5 mm in width,            held upright, strong, color 144A to 144B and 157D towards            apex, glabrous surface.        -   Pedicels.—About 0.75 mm in length and 0.5 mm in width and            157D in color, glabrous surface.-   Reproductive organs:    -   -   Gynoecium.—2 Pistils, club-shaped, about 1.8 mm in length,            stigma N155A in color and minute, style is about 1.7 mm in            length and N155A in color, ovary is superior and N155A in            color.        -   Androcoecium.—About 10 stamens, anthers are broadly ovate in            shape, basifixed, about 0.2 mm in length and width and N155A            in color, filaments are about 1.8 mm in length and 71C in            color, pollen is low in quantity and 158D in color.        -   Seed.—No seed development has been observed.

1. A new and distinct cultivar of Astilbe plant named ‘White Sensation’as herein illustrated and described.